Room Temperature Operation of UV-LED Composed of TCO Hetero p-n Junction, p-SrCu2O2/n-ZnO

2000 ◽  
Vol 623 ◽  
Author(s):  
Hiromichi Ohta ◽  
Ken-Ichi Kawamura ◽  
Masahiro Orita ◽  
Nobuhiko Sarukura ◽  
Masahiro Hirano ◽  
...  
Keyword(s):  
Room Temperature ◽  
Uv Light ◽  
Forward Bias ◽  
Photo Luminescence ◽  
State Density ◽  
Turn On ◽  
Forward Bias Voltage ◽  
Uv Led ◽  
The Difference ◽  
Room Temperature Operation

AbstractRoom temperature operation of UV LED is realized for the first time using a hetero p-n junction composed of transparent conductive oxides, p-SrCu2O2 and n-ZnO. Ni/SrCu2O2/ZnO/ITO multi-layered film was epitaxially grown on an extremely flat YSZ (111) surface by a PLD. The grown films were processed by a conventional photolithography, followed by reactive ion etching to fabricate p-n junction diode. The resultant device exhibited rectifying I-V characteristics inherent to p-n junction whose turn-on voltage was about 1.5V. A relatively sharp electro-luminescence band centered at 382nm was generated when applying the forward bias voltage larger than the turn-on voltage of 3V. The red shift in the EL peak was noticed from that of photo-luminescence (377nm), which was most likely due to the difference in the excited state density between the emission processes. The EL band is attributed to transition in ZnO, probably to that associated with electron-hole plasma. The photo-voltage was also generated when the p-n junction was irradiated with UV light of which energy coincided with both exciton and band-to-band transitions in ZnO.

Electrical Transport Mechanisms in p+a-SiC:H/n c-Si Heterojunctions: dark J-V-T Characteristics

1996 ◽  
Vol 420 ◽  
Author(s):  
M. W. M van Cleef ◽  
M. W. H. Philippens ◽  
F. A. Rubinelli ◽  
M. Kolter ◽  
R. E. I. Schropp
Keyword(s):  
Bias Voltage ◽  
Electrical Transport ◽  
Room Temperature ◽  
Crystalline Silicon ◽  
Forward Bias ◽  
Equivalent Circuit Model ◽  
Interface State ◽  
Transport Mechanisms ◽  
Forward Bias Voltage ◽  
State Densities

AbstractIn the present paper we show results of dark current-voltage measurements performed on p+ a- SiC:H/n c-Si heterojunction diodes at various temperatures (100–400K). We investigated the voltage derivative of these J-V curves in order to the distinguish possible current transport mechanisms. It was found that for low temperatures (<300K), the current is determined by recombination of carriers in the crystalline silicon, whereas at high temperature (>300 K), by a tunnelling mechanism. At room temperature, both mechanisms contribute to the current. By using an equivalent circuit model and detailed numerical simulations we have interpreted our experimental characteristics. The simulations done at room temperature, show that at low forward bias voltage the current is controlled by recombination in the crystalline silicon and that at high forward bias voltage by a combination of multi-step tunnelling and a-SiC:H series resistance. For interface state densities equal to or higher than 1012 cm−2, the recombination was found to be dominated by the states at the amorphous-crystalline silicon interface.

Drift Mobility Measurements in Porous Silicon

1996 ◽  
Vol 420 ◽  
Author(s):  
L. Tsybeskov ◽  
C. Peng ◽  
P. M. Fauchet ◽  
Q. Gu ◽  
E. A. Schiff
Keyword(s):  
Porous Silicon ◽  
Response Time ◽  
Room Temperature ◽  
Forward Bias ◽  
Drift Mobility ◽  
Maximum Response ◽  
Forward Bias Voltage ◽  
Maximum Response Time ◽  
Temperature Time ◽  
Applied Forward Bias

AbstractModulated electroluminescence (EL) measurements performed on a series of porous silicon (PSi) diodes are presented. The maximum response time of the devices scales with the square of the PSi layer thickness and inversely with the applied forward bias voltage. These scaling results indicate that the maximum response time is a carrier transit time from which a drift mobility μ of 10−4 cm2/Vs is deduced at room temperature. Time-of-flight transport measurements on PSi are in qualitative agreement with this value for μ in addition, they identify μ as the electron mobility and show that transport is dispersive, in contrast to the interpretation of the modulated EL experiments.

scholarly journals UV-LED Photo-Activated Room Temperature NO2 Sensors Based on Nanostructured ZnO/AlN Thin Films

Proceedings ◽  
2019 ◽  
Vol 2 (13) ◽  
pp. 888 ◽  
Author(s):  
Tony Granz ◽  
Marius Temming ◽  
Jiushuai Xu ◽  
Qomaruddin ◽  
Cristian Fabrega ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Gas Sensing ◽  
Uv Light ◽  
Volume Ratio ◽  
Si Substrate ◽  
Strong Reduction ◽  
Light Emitting ◽  
Uv Led ◽  
Increased Sensitivity

UV-light emitting diodes (395–278 nm) were used to investigate the gas sensing attributes of planar and nanostructured ZnO/AlN thin films on Si substrate towards NO2 at room temperature. A significant increased sensitivity ((Rg − Ra)/Ra = 65.3 ppm NO2 in air) and a strong reduction in recovery time (Trec = 14 min) were already observed for the planar ZnO/AlN thin films under UV-B (305 nm) irradiation compared to the other UV wavelengths, while the device showed no obvious response in dark. By enlarging the surface-to-volume ratio of the sensors (i.e., creating nanostructured ZnO/AlN thin films), an increased response time is expected to be observed.

scholarly journals Constant Optical Power Operation of an Ultraviolet LED Controlled by a Smartphone

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4707
Author(s):  
Ching-Hua Chen ◽  
Jia-Jun Zhang ◽  
Chang-Han Wang ◽  
Yu-Chia Chang ◽  
Pinghui S. Yeh
Keyword(s):  
Uv Light ◽  
Light Output ◽  
Color Temperature ◽  
Constant Light ◽  
Driving Voltage ◽  
Light Power ◽  
Monolithically Integrated ◽  
Uv Led ◽  
Power Operation ◽  
Arduino Uno

Constant light power operation of an ultraviolet (UV) LED based on portable low-cost instrumentation and a monolithically integrated monitoring photodiode (MPD) has been reported for the first time. UV light irradiation has become one of the essential measures for disinfection and sterilization. Monitoring and maintaining a specified light power level is important to meet the criteria of sterilization. We built a module composed of a monolithically integrated UV LED and MPD, a transimpedance amplifier, an Arduino Uno card, a digital-to-analog converter and a Bluetooth transceiver. An Android App that we wrote remotely controlled the UV LED module via Bluetooth. The Arduino Uno card was programmed to receive demands from the smartphone, sent a driving voltage to the LED and returned the present MPD voltage to the smartphone. A feedback loop was used to adjust the LED voltage for maintaining a constant light output. We successfully demonstrated the functioning of remote control of the App, and the resultant UV LED measured power remained the same as the setting power. This setup can also be applied to visible or white LEDs for controlling/maintaining mixed light’s chromaticity coordinates or color temperature. With such controlling and internet capability, custom profiling and maintenance of precision lighting remotely would be possible.

scholarly journals Zirconium-Doped Chromium IV Oxide Nanocomposites: Synthesis, Characterization, and Photocatalysis towards the Degradation of Organic Dyes

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 117
Author(s):  
Zahir Muhammad ◽  
Farman Ali ◽  
Muhammad Sajjad ◽  
Nisar Ali ◽  
Muhammad Bilal ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Solid State ◽  
Room Temperature ◽  
Organic Dyes ◽  
Uv Light ◽  
Heterogeneous Photocatalysis ◽  
Ft Ir ◽  
Complete Mineralization

Degradation of organic dyes and their byproducts by heterogeneous photocatalysts is an essential process, as these dyes can be potentially discharged in wastewater and threaten aquatic and xerophyte life. Therefore, their complete mineralization into nontoxic components (water and salt) is necessary through the process of heterogeneous photocatalysis. In this study, Zr/CrO2 (Zirconium-doped chromium IV oxide) nanocomposite-based photocatalysts with different compositions (1, 3, 5, 7 & 9 wt.%) were prepared by an environmentally friendly, solid-state reaction at room temperature. The as-prepared samples were calcined under air at 450 °C in a furnace for a specific period of time. The synthesis of Zr/CrO2 photocatalysts was confirmed by various techniques, including XRD, SEM, EDX, FT-IR, UV-Vis, and BET. The photocatalytic properties of all samples were tested towards the degradation of methylene blue and methyl orange organic dyes under UV light. The results revealed a concentration-dependent photocatalytic activity of photocatalysts, which increased the amount of dopant (up to 5 wt.%). However, the degradation efficiency of the catalysts decreased upon further increasing the amount of dopant due to the recombination of holes and photoexcited electrons.

Force‐Induced Turn‐On Persistent Room‐Temperature Phosphorescence in Purely Organic Luminogen

2021 ◽  
Author(s):  
Jia Ren ◽  
Yunsheng Wang ◽  
Yu Tian ◽  
Zhenjiang Liu ◽  
Xiangheng Xiao ◽  
...  
Keyword(s):  
Room Temperature ◽  
Room Temperature Phosphorescence ◽  
Turn On

Anselm's Formula and the Logic of ‘God’

1973 ◽  
Vol 9 (3) ◽  
pp. 279-288
Author(s):  
Paul M. van Buren
Keyword(s):  
Ontological Argument ◽  
Turn On ◽  
The Difference

Anselm built his meditation Proslogion on the formula ‘that than which nothing greater can be conceived’. The peculiarity of this phrase has been often remarked but not, I believe, fully appreciated. Properly understood, I shall argue, this formula, although unable to support the so-called ontological argument, throws important light on the logic of the religious use of the word ‘God’. My argument will turn on the difference between the two uses of the verb ‘conceive’ in Anselm's claim that we can conceive of that than which nothing greater can be conceived.

ROOM TEMPERATURE PHOTOLUMINESCENCE OF POLYCRYSTALLINE SIC PREPARED FROM CARBON-SATURATED SI MELT

2002 ◽  
Vol 16 (06n07) ◽  
pp. 1047-1051
Author(s):  
JIANPING MA ◽  
ZHIMING CHEN ◽  
GANG LU ◽  
MINGBIN YU ◽  
LIANMAO HANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Uv Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Composition And Structure ◽  
Light Excitation ◽  
Scanning Electron

Intense photoluminescence (PL) has been observed at room temperature from the polycrystalline SiC samples prepared from carbon-saturated Si melt at a temperature ranging from 1500 to 1650°C. Composition and structure of the samples have been confirmed by means of X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. PL measurements with 325 nm UV light excitation revealed that the room temperature PL spectrum of the samples consists of 3 luminescent bands, the peak energies of which are 2.38 eV, 2.77 eV and 3.06 eV, respectively. The 2.38 eV band is much stronger than the others. It is suggested that some extrinsic PL mechanisms associated with defect or interface states would be responsible to the intensive PL observed at room temperature.

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